无法用处理程序解析CalledFromWronThreadException

我会尽量保持简单:

在我的主要活动中,我做了一个处理程序:

public class ARViewer extends ARDisplayActivity {

    public final MHandler mHandler = new MHandler(this);

 public void onCreate(Bundle savedInstanceState) {
...

mhandler类:

public final class MHandler extends Handler{

        //main activity
 private ARViewer arnv;

        public MHandler(ARViewer arnv){
  this.arnv = arnv;
 }

        @Override
 public void handleMessage(Message msg) {
            ...
            case H_RR :
                  arnv.setContentView(R.layout.routeplanner);    
                  break;
            ...
  super.handleMessage(msg);
 }
}

但是,如果我从另一个类中的回调函数调用handleMessage方法,当然是从另一个线程调用,我仍然会收到异常消息: CalledFromWrongThreadException (Only the original thread that created a view hierarchy can touch its views) :

public void rFound(Route route) {
           Message msg = new Message();
           msg.what = MHandler.H_RR;
           ARViewer.arnv.mHandler.handleMessage(msg);
}